Nest-type associated microclimatic conditions as potential drivers of ectoparasite infestations in African penguin nests.

Nest design and characteristics can influence the microclimatic conditions in the nest. Nest-dwelling ectoparasites are sensitive to temperature and moisture and as such the conditions in the nest can influence parasite infestations. The endangered African penguin (Spheniscus demersus) breeds in different nest types and as yet little is known with regard to the microclimate and parasite infestation within these nests. This study characterized the microclimatic conditions in natural open, natural covered (with vegetation) and artificial nests, and assessed the relationship between nest characteristics (type, age, distance from the coast, orientation and entrance opening) and in-nest ectoparasite infestations and the health of African penguins in Stony Point, South Africa. Penguins (50 adults and 192 chicks) and their nests (n = 308) were sampled in 2016 and 2017. Soil temperature was higher in artificial than in natural nests, and soil and nest material moisture was lower in artificial and natural covered nests than natural open. Ectoparasite infestations were higher under warmer and drier conditions, in artificial nests and nests near the coastline. Penguin (adult and chick) body mass and chick body condition were lower in warmer nests and total plasma protein (in adults and checks) was lower in drier nests. Given the potential adverse effects of ectoparasites on host species, it is recommended that conservation agencies implement a monitoring programme to assess the ectoparasite infestation in artificial nests across multiple colonies. This information will facilitate a more holistic penguin conservation management plan that may prevent further detrimental effects on this endangered penguin species.